Usually Sync still has your data. Did anything come back -- bookmarks, other logins?

Did your Windows reset store your old data in a new temporary folder called

C:\Windows.old

Can you find such a folder on your system?

If so:

Before proceeding, please set Windows to show you hidden files and folders: https://support.microsoft.com/en-us/help/14201/windows-show-hidden-files

Then check here:

C:\Windows.old\Users\<username>\AppData\Roaming\Mozilla\Firefox\Profiles\

You might just have one profile folder, or you might have more than one. One way to tell whether a profile was one you were using recently is to check the date/time stamp on a file like places.sqlite or check the dates in the file names in the bookmarkbackups folder.

Anything there that we could work with?

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